Yeah. They’re “wired” to have the Main Light Source (e.g. moon) in a certain area of their visual field. It allows for navigation. If it strays too far from that area of their visual field, they’re off course.

Well, a bulb is really fucking close, so any movement or adjustment or turn is gonna “move the navigation light”, so they have to swerve to get it back in the right spot.

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It’s like in Skyrim or Fallout, where the pip on your compass moves more as you get closer. Except there’s actually a key in some dead guy’s pocket, and his corpse clipped into the basement so every step you take, that compass pip goes flying, to the other sidecar telling you to keep turning around because it’s always just behind yiu again.